1. Technical Field
The present invention relates generally to a method and system of manufacturing integrated circuit (IC) chips and the IC chips formed by the implementation of the method. More specifically, the present invention relates to methods and systems to increase the capacitance of a storage node by increasing the deep trench sidewall surface area.
2. Background Art
The trend in semiconductor device fabrication towards increasing density of circuit components requires that smaller areas of the circuit be devoted to isolation of the circuit components and capacitive storage areas. The need to reduce the surface area used for circuit components such as isolation structures and large area capacitor devices has resulted in the development of structures vertically oriented with respect to the plane of the substrate surface. These vertical structures may consist of some type of trench structure sunk into the semiconductor substrate and are positioned between charge carrying components of adjacent transistors. The effective surface area of the capacitor was maintained by placing the capacitor on the sides of a narrow trench etched into the silicon. The utilization of a trench structure enables the formation of a structure having large volume while minimizing the amount of surface area consumed.
Ever decreasing lithographic images drive smaller and smaller trench sizes with a corresponding reduction in the storage charge which may be held in a capacitor trench cell. Less charges creates both read problems and data integrity problems. One way to increase charge storage is by increasing the trench area using the same real estate (space) of the chip.